Ok, OK... Sorry for the lack of proper info. It is in a Toyota Tacoma 2008 Double Cab Long bed, with the 4.0 V6 engine. the engine has had Mobil 1 5W-30 until 60,000 miles, then I switched to RP 5w-30 until this week when I went over to Rotella T6 5w-40 at 76,000 miles. So I ran the RP for about 16,000 miles. I will say that even with the Mobil1 the engine always has looked very clean (by looking into the filler cap, which lets you see into the valve cover some) I just thought the RP was not holding up well, and thats why I stated it felt clacky. I t did feel clacky and that was a just feeling as the engine is not nearly as clacky now, like I mentioned it feels cushioned! i have the last sample of RP 5w-30 ready to go to the Lab, as soon as i get around to it. i will also send out the first sample of T6 when I change it out. I am very happy I made this change, and I would not have had the information I wanted if it was not for BITOG! Thanks to all of the users here that provide samples and information for others to see. It was research I found here that helped me discover and decide to change to a new oil. I just had a problem with justifying the cost of the RP when there are other oils out there that will hold up to my OCI just fine and cost way less. My OCI by the way is 5k, I have been doing it for ever and will remain doing that. like I said I am stoked about the change and feel alot happier about the engine now.